use docker-client 2.3.0
explicit PersistentAtomicReference interrupts

Interrupting a thread blocking on PersistentAtomicReference i/o will now
cause PersistentAtomicReference to throw an InterruptedException instead
of a RuntimeException. This enable the agent to better deal with
interruptions.
interruptible PersistentAtomicReference ctor
Merge pull request #17 from spotify/dano/iterruptible-persistent-atomic-reference

explicit PersistentAtomicReference interrupts